Sheet-metal bending and forming machine



Jan. 12 192s.

A' C. G. CRONWALL v'SHEET IIBTAL BBNDING AND FORIING MACHINE Filed Haren7,' 192s 2 sheets-sheet 1 Jan. 12v, 1926.

Y c. G. .CRONwALL suban@ mammie AND Forum@ uc3m;

2' Sheets-Sheet 2 Filed llaroh 7, 1925 Patented Jan. l, 1926.

UNITED STATES CARL GUSTAV CRONWALL, 0F CHICAGO, ILLINOIS.

SHEET-METAL BENDING AND FORMING MACHINE.

Application led March 7, 1925. Serial No. 13,720.

T 0 all whom t may concern: l

Be it known that I, CARL Gus'rAv CRON- WALL, a citizen of the UnitedStates, residing at Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inSheet-Metal Bending and Forming Machines, of which the following is aspecification.

This invention relates, generally, to metal working, but has particularrelation to'improvements in sheet metal bending and forming machines,and it consists in certain peculiarities of the construction, novelfeatures, arrangement and combination of the various parts thereof aswill be hereinafter more fully set forth and specifically claimed.

The principal object of the invention is the provision of a machine forbending and forming pieces of sheet metal into various shapes fordifferent uses or purposes, which shall be simple and inexpensive inconstruction, strong, durable and eiiicient in operation.

Another, and an important object, is the provision in such a machine, ofmeans preferably manually operated for actuating a movable die orforming element-carrying member thereof with great force and effect, aswell as with accuracy and uniformity throughout its length ordimensions, yet in such a way as to require but little exertion on thepart of the operator.

Still another object is to provide the ydie.

or forming element-carrying-members of the machine with means wherebydies or matrices of different shapes can be interchangeably used, andcan be quickly and readily removed and replaced for this purpose.

Other objects and advantages of the invention will be disclosed in thefollowing description and explanation, which will be more readilyunderstood when read in conjunction with the accompanying drawings, inwhich embodiments of the invention are illustrated, it being understoodthat changes and modifications may be resorted to without a departurefrom the spirit of the invention, so long as they fall within the scopeof the appended claims forming a' part hereof.

In the drawings,-

Fig. 1 is a plan View of a machine ernbodying one form of the invention.

Fig. 2 is a side view in elevation thereof showing the parts bycontinuous lines in their normal positions, or in the positions theywill occupy when ready to receive a piece of sheet metalbetween theforming members or dies thereof and by dotted lines about the positionsthe parts will occupy when moved to their forming or operativepositions. A

Fig. 3 is an enlarged fragmental perspective View of a portion of thebaseor fixed die carrying member ofthe machine, showing the constructionof one end and a part of the lower surfacethereof.

Fig. 4 is a detached perspective View of a portion of the means foractuating the movable die carrying member.

Fig. 5 is a view in side elevation illustrating a modification in theconstruction of the lower portion of the base or fixed die carryingmember.

lig. 6 is an end view in elevation thereof, an l Fig. 7 is an enlargedvertical sectional view taken on line 7 7 of Fig. 5 looking in thedirection indicated by the arrows.y

Like numerals of reference refer to corresponding parts throughout the'different views of the drawing.

Referring now more particularly to Figs. 1 to 4 inclusive of thedrawings, the reference numeral 10 designates as a whole the base of themachine, which base may be made ofv any suitable size, form andmaterial, but by preference of an elongated rectangular shape asshown.At each of its ends the base 10 is provided with an upright 11 each ofwhich is by preference of less thickness than that of the base 10 andare employed to act as guides for the movable die or formingelement-carrying member 12 which is also of an elongated substantiallyrectangular shape and has at each of its ends a slot or guideway 13 forthe reception of the guides 11 or uprights. The base 10 has a flat uppersurface and is provided'in its upper portion with a series of spacedpins 14 arranged in a row' at the medial line between the side surfacesof said base and so as to project a slight distance above its uppersurface, as is clearly shown in Figs. 2, 5 and 7 of the drawings. Theseupwardly projecting pins 14 are employed as keepers for a matrix or die15 which is provided in its lower surface with a number of openings i6corresponding in positionj and size with the pins l-/l which tit intosaid openings. The upper portion of the die or matrix 15 may be providedwith a cavity l? of any desired shape. The base l() may be supported inany suitable or well known way butby lpreference by means of a pair oflegs 18 located near each end thereof, one member of each pair of saidlegs being located on opposite sides of the base and secured thereto attheir upper portions in any suitable way. One end of the base l0 hasmounted thereon a plate l) which is provided with a pair of spaced and'transverselifv aperture'd bearingl lugs or bosses 20, see Fi,

l to. 3, inclusive the drawings. tlust below the lower end of the plate19 the base l0 is downwardly beveled as at 2l, see Fig. 3, and adjacentthe lower end of the beveled portion 2l the bottom of the base lO isprovided with` aL transversely disposed upwardlyv curved recess 22 atabout the middle` of which is mounted and secured in any well known wayto the` base an apertured bearing member 23, which member and curvedrecess are employed for the purpose to be presently explained. Near itsopposite end the base 10 is provided in its bottom with anothertransversely` disposed upwardly curved recess or bearing surface 24which is also equipped with a transversely apertured bearing member',which, like the bearing member 23 above mentioned, is secured in anywell known way to the base 10 at about the middle of the recess 24.

The lower surface of the movablel die carrying member l2 is providedwith a longi-v tudinally disposed channel 25 in which is locatedl a dieor forming member 26 of any desired formation, for co-operation with theadjacent surface of the die or forming member i5, and said member 2G maybe detachably held in position within said channel by means of a numberof screws 27 seated in suitable transverse openings in the member l2 andextended through registering openings provided in the upper portion ofsaid die member.

Pivotally mounted at one of its ends between the apertured bosses orlugs 2O on the plate 19 at the operators end of the machine, is a link28 the other end of which is pivotally mounted between the lowerportions of the prongs 29 with which the operating lever 30 is provided,at its lower end. A bell crank lever, designated as a whole by thereference numeral 3l and comprisingl a pair of upwardly extended andvspaced parallel arms32 and 33, and aV pair of downwardly extended andspaced parallel arms 34 and 35 (see Fig. 4) and having a transverseopening 36 and a vertical slot 37 in its front end, is fulcrumed at saidend on the bearing member 23 located near the operating end of the basel0 in such a way that the rounded portions o f the front or upper end ofthe bell crank lever 3l will contact withL the surface of the curvedrecess 22 ony each side of the bearing member 23, thus providing a veryefficient and stable bearing connection between the said bell cranklever and the base of the machine,

The upper ends ofthe arms 32 and 33 are pivotally connected to the sidesof the lever 30 at the upper portion of the prongs 29 thereof, will bereadily understood byv reference to Figs. 2 and i of the drawings, insuch a way as to stride the link 2,8150 as to permit free movements ofthe parts. At about their juncture with the arms 34 and 35 of the bell33 each has pivotaliyl connected thereto the lower end of a link S8which is pivotally secured to the upper portion of the movable diecarrying member l2 near the operatos end of the machine and on each sidethereof. Pivotally secured at one of its ends between the free ends ofthe arms 34. and 35 of the bell crank lever 3l is a tie bar or link 39which extends longitudinally with respect to the base l0 and under thesame between the members of each pair of its legs 18, and is pivotallyconnected at its other end to the lower end of a pair of parallel spacedarms l0 connected together for unitary movement and by preference of thesame construction as the arms 34 and of the bell crank lever 3l abovedescribed. The upper ends of the arms 4c() are rounded as at all toco-act with the upwardly curved bearing surface 2dand are ivotallymounted on a shaft .42 journaled in the bearing member 23 located on thebottom of the base l0 near its end opposite that on which the operatinglever 30 is mounted.

lt will be understood that the upper ends of the arms /l-O are providedwith a space or slot 37 for the reception of the said bearing member 23in a similar manner to that shown in Fig. ll with respect to the arms84tand of the bell crank lever. However, it vill be observed that thearms 32 and 33 of the bell crank l ver arc omitted from the structure ofthe arms Ll-O, and it will be clearly seen in `Figs. 2 and 5 of thedrawings that a link L13, located on each side of the machine at the endthereof adjacent the pivot or fulcrum 4t2 for the arms lO, is pivotallysecured at its lower end to an upwardly extended boss ai on the arms 40,and at its upper end pivotally connected to the upper portion of themovable die'carrying member l2 near its end opposite the operatinglever.

In Fig. 5 of the drawings the modiicacrank lever 3l, the arms 32 and'tion consists in dispensing with the bearing members 23 employed in theconstruction illustrated in Figs. l to 4 inclusive and above describedand in lieu thereof in supporting the upper ends of the arms 34 and 35of the bell crank lever'l and the upper ends of the arms 40 by means ofbrackets 45 one of which is vertically mounted on each side of the base10 near each of its ends directly above the curved bearing portions 22and 24 and in such a way that the lower ends of each pair of saidbrackets will depend slightly below the lower surface of the base, asisclearly shown in Fig. 5 of the drawings. In this modification the upperends of the arms 34 and 40 are journaled between the depending ends ofthe brackets and the rounded portions of said upper ends will co-operatewith the curved bearing surfaces 22 and 24 in a manner so as to providevery stable and efficient bearings. y

From the'foregoing, and by reference to the drawings, it will be readilyunderstood and clearly seen that by the construction and arrangement ofthe above named lever and links employed for the actuation of themovable die or f forming element carrying member, great pressure orforce will be imparted to said movable member by the downward movementof the operating lever 30 and with a minimum expenditure of power orenergy applied thereto. It is also manifest that, assuming the parts arein the positions shown in Figs. 2 and 5 of the drawings and it isdesired to-give formation to a piece of material such as a piece ofsheet metal, all that is necessary is to place the same between the diesor forming members 15 and 26 which may be of any construction to givethe desired formation to the material, when by turning the operatinglever downwardly to about the position shown by dotted lines in Fig. 2,the

dies or forming members will be caused to co-operate with oneanother soas to clamp and give form to the piece of material being operated on. Inthis operation of the downward movement of the operating lever 30, it isobvious that the links 28 and 89 will co-operate with the lever, thearms of the bell crank lever 31, the arms 40 and links 38 and 43 in themanner of toggles and that thereby great force or pressure will beimparted to the movable die carrying member.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent is 1. In a machine of the class described,the combination with a suitably mounted base, of a forming elementmounted thereon, another forming element and a carrying member thereformovably mounted with respect to said base for the co-operation of theirforming elements, means for the movement of said movable member towardand from said base, said means including a link pivoted at one of itsends to an end of the base, anoperating lever pivoted at one of its endsto the other end of said link, and leverage compounding means havingpivotal connection with said operating lever above its pivot and withthe ends of the base and the ends of the said movable member.

2. In a machine of the class described, the combination with a suitablymounted base having upwardly extended guiding means at its ends, of aforming element longitudinally and detachably mounted on the upperportion. of said base, a member movably mounted above the base andhaving means (zo-acting with said guiding means thereof, a formingelement detachably and longitudinally mounted on the lower surface ofthe last named member for' co-operation with the forming element of thebase, means for the movement of said movable member toward and from saidbase, said means including a link pivoted at one of its ends to an endof the base, an operating lever ivoted at one of its ends to the otherend o said link, and leverage compounding means having pivotalconnection with said operating lever above its pivot and with the endsof the base and the ends of said movable member.

3. Ina machine of the class described, the combination with a suitablymounted base having in its lower surface near each of its ends anupwardly curved bearing re-V cess, a'forming element detachably mountedon the upper surface of the base, a member mounted for vertical movementand guidance above said base, a forming element mounted on the lowersurface of the last named member for co-operation with the formingelement of the base, a pair of arms -pivotally mounted near each end ofthe base and below the same, said arms having their ends rounded andarranged for coaction with said recesses, connections ivot ally unitingthe upper portions of sai arms to said movable member near its ends, a

link connecting the lower ends of said arms,l

a link pivotally mounted at one of its ends on an end of the base, anoperating lever pivoted at its lower end on the other end of said link,and a connection uniting said lever above its pivot to the upper portionof one pair of said arms.

4. In a machine of the class described, the combination with a suitablymounted base having in its lower surface near each of its ends anupwardly curved transverse bearing recess, of an apertured bearingmember mounted in each of said recesses, a forming element mounted onthe u per surface of the base, a member mounte for vertical movement andguidance above said base, a forming element mounted on the lower surfaceof the last named member for Ifo-ope'sion with the forming element ofthe base, a pair of arms pivotaliy mounted on earch of said aperture'dbearing members below the base, said arms har/'ing their upper endsrounded and arranged for co- :retion with said recesses, Connectionspirotally uniting' the upper Vportions o' said arms to said movablemember near its ends, a

CARL GUSTAV "oRoivAL'L,

